In this forum I post the changes on the DEVELOPER version of the game.
These versions are (at the time i post them) not yet published to google play, only registered testers can download it and test it before publishing.

there are tiers to all existing sieges and ships
I also added ballista (3 tiers)
all techs are now tied to the right units (upgrades will work like those for other human units)
I corrected a bug for orc archer (master tier was considered a 2x2 unit)